Radiometers of the type disclosed herein are used to measure and calibrate electro-optic test sets that generate low levels of laser energy in the 1064 nm and 1540-1570 nm wavelengths. In the prior art, electro-optic test sets only required calibration at a wavelength of 1064 nm. A radiometer known as the APD800, developed through the NAVSEA R&D program, fulfilled this requirement. New “eyesafe” (1540-1570 nm) wavelengths have been added to test sets for support of new military rangefinders. The APD800 cannot detect this new wavelength range.
Another radiometer, namely the PLR-100 radiometer, also developed through the NAVSEA R&D program, is limited in that it is too slow to accurately catch fast laser pulses and it is not sensitive enough to measure the full range of test sets output. There is no commercially available instrument that can measure signals used for calibrating the test sets that test minimum sensitivity of laser rangefinders and designators.
The only instrument that is similar is a peak power measurement system manufactured by Delta Developments known as the Peak Power Measurement Head model HL. However, it can only be used at a single predetermined wavelength and can only measure signals down to 2 μW/cm2. By way of contrast, the invented D-ESR is capable of measurements down to 0.5 nW/cm2. The speed of the Delta Developments unit is 10 ns FWHM (full width half maximum) compared with 2.3 ns for the invented D-ESR. The invented D-ESR radiometer may have potential use in support of LIDAR (light detection and ranging) as well as its intended use in the support of laser rangefinders and designators.